postal.rapidsupport.com.pk has no MX records.
Question and response
Question
dig postal.rapidsupport.com.pk. MX
Answer
The response has no answer records.
Authority
rapidsupport.com.pk. 1800 SOA shane.ns.cloudflare.com. dns.cloudflare.com. 2395460927 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0